Effects of spray-dying temperatures and carriers on physical and antioxidant properties of lemongrass leaf extract powder

Abstract

The objectives of this research were to identify properties influences of spray-drying temperature and carriers on physical and antioxidant properties of lemongrass leaf extract powder. Two independent variables including inlet temperature (1100C, 1200C, 1300C, 1400C and 1500C) and carriers (Gum Arabic, Maltodextrin, Gum Arabic: Maltodextrin mixture) were studied. The process was carried out using Lab Plant SD06 spray dryer. Bulk density, moisture content, solubility, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant capacity (AC) of the obtained powder were analyzed. Moisture content, TPC and TFC were negatively affected by temperature while bulk density, solubility and AC were positively correlated to heating. Among all the have been analyzed, the sample produced at 1100C had the highest TPC (3.02 mg GAE/ 100g) and TFC (541.82 mg CE/ 100g DW) compared to the others. However, due to high moisture content which is not suitable for the shelf-life of powder product, this condition cannot be recommended as a favorable condition for lemongrass powder manufacturing. Quality of the lemongrass powders were also influenced by different kinds of carriers. The powder produced by mixing with Maltodextrin at 1200C retained the relative high levels of AC, TFC and TPC with a high water soluble ability as compared to the others, matching well with quality requirements for an instant powder product. Keywords: lemongrass powder, spray-drying, inlet temperatures, carriers, total phenolic content, total flavonoid content, antioxidant capacity